Compact integrated brake system

ABSTRACT

A mechanically applied spring release brake ( 50 ) having a single small diameter dynamic seal ( 46 ) is integrated into a wheel and tire to provide for a small package utilized in forklifts, wheel trucks and other industrial vehicles.

FIELD TO WHICH THE INVENTION RELATES

This invention relates to an integrated brake and wheel package.

BACKGROUND OF THE INVENTION

Brakes have been used for stopping the movement of rotary objects suchas scissorlifts or tow motor wheels, chain lift pulleys and others.These brakes come with drums, disks, increasing ramps, and other type ofenergizing devices. Typically, these energizing devices are large(necessitating a sizable diameter package), or require a separatemounting adjacent to the effected rotary device (necessitating a longerpackage). An example of such energizing devices are the Ausco series ofbrakes as typified in both the radial and axial versions (the formerbeing inside a separate wheel and the latter being displaced laterallyoff of the end of a separate wheel axle). Other applications use largediameter external brake disks or internal brake drums (as for exampleused in present day separate wheel rim automobiles). Attempts tointegrate the brake and wheel frequently have resulted in large sizeddevices (R. W. Brown U.S. Pat. No. 2,381,393, for example) or haveproduced complex mechanisms (Lemaire U.S. Pat. No. 5,333,705, HydraulicMotor and Brake, for example).

The cost, complexity and/or size of these units have not produced asuitable integration of wheel and brake.

SUMMARY OF THE INVENTION

It is an object of this invention to integrate a disk brake inside asupported rotary member.

It is an object of this invention to reduce the cost of providing abraked wheel.

It is another object of this invention to reduce the stress on a wheelsystem when a hydraulically released brake is actuated.

It is a further object of this invention to provide for a compactmechanical brake application.

It is another object of this invention to provide for a more adaptablewheel brake.

It is a further object of this invention to reduce the physical andhydraulic complexity of the device associated with a brake.

It is another object of this invention to provide for a high torquemechanical brake in a small diameter unit.

It is yet another object of this invention to reduce the number ofdynamic seals on rotary members in a brake.

It is still a further object of this invention to increase the speed of,and to simplify, the manufacturing integration of a braking rotarycomponent into an associated vehicle.

Other objects and a more complete understanding of the invention may behad by referring to the drawing in which:

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a lateral cross-sectional view of an integratedwheel/brake/spindle combination. This FIG was taken substantially alonglines 1-1 in FIG. 3;

FIG. 2 is a further lateral cross-sectional view of the integratedwheel/brake/spindle of the present invention. This FIG was takensubstantially along lines 2-2 in FIG. 3;

FIG. 3 is a view of the left hand side of the unit of FIG. 1;

FIG. 4 is a view of the right hand side of the unit of FIG. 1;

FIG. 5 is a perspective view of the completed unit of FIG. 1; and,

FIG. 6 is a hydraulically applied multiple coil spring released brakeincorporating the invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention of this application relates to a spindle mounted rotarymember including an engagement mechanism.

The example brake assembly shown includes a braking mechanism 50 locatedbetween a spindle 20 and a tire 100.

The spindle 20 serves to rotatively mount the tire 100 and containedbraking mechanism 50 to an associated part. An example of thisassociated part would be the vehicle frame of a scissorlift. Theparticular embodiment would be bolted onto such frame (shown in dottedlines 200 in FIG. 1) from the backside by bolts 201. This would tightlyretain the mounting plate 21 of the spindle to the frame 200 against theweight and dynamic loading to and from the vehicle or device (such as ascissorlift) and the tire 100. Note that the particular mechanism 10disclosed is spring applied and pressure released braking mechanism.Therefore, a hole 202 would be provided in the frame in order to allow asuitable selective pressurization hydraulic line 205 to beinterconnected to the brake assembly 10. (This hole 202 also aids inlocalizing and weight transfer between the spindle and the frame 200 dueto flange 23 engaging the sides of the hole 202.)

In addition to the mounting plate 21, the spindle 20 has an enlargedprimary bearing area 30, a relatively reduced secondary bearing area 40and a reduced oil passage extension 45.

The enlarged main bearing section 30 serves to carry the primary weightof the vehicle by forming the primary interconnection for the mainbearing 31 and the primary torque by the attachment of the reactiondisks 33 thereto. It is preferred that the main weight loading of thewheel be through this ball bearing (being of large size and of proximityto the enlarged diameter plate 21 and frame, it can dissipate heat moreefficiently). In addition, the preferred main bearing 31 as shown is aball bearing located between the spindle mounting plate 21 and twoseparate snap rings 35. One snap ring is internal to the spindle 20 andthe other is external to plate 63. Plate 63 has a small inner lip 65adjacent to the outer inside edge of bearing 31. This allows the bearingat this location to take the forces inwardly and outwardly between thewheel 100 to the frame 200 (i.e., separate thrust bearings are notnecessary).

The secondary bearing area 40 aids in the support of the weight loadingof the wheel. Incorporating a needle bearing 41 at this location alsoallows room and physical placement for the parts of the brakingmechanism 50 radially outward therefrom. This lowers the necessarydiameter of the housing 60 in respect to alternative bearings. It alsoallows the bearing outward of most of the braking mechanism 50, thusaiding in reducing wobble and in localizing the later described dynamicseal 46.

Located off the end of the secondary bearing area 40 is a reduced oilpassage extension 45. This reduced oil passage section is surrounded bythe main dynamic seal 46 for the actuation mechanism. By being reducedin diameter, this has the effect of reducing the axial thrust of the“piston area” between the braking mechanism 50 and the spindle 20 duringpressurization from line 205 (compare the area of the reduced oilpassage extension 45 which would be necessary if a dynamic high pressureseal was located about the larger diameter 30 of the spindle with thatof the main bearing 30, for example). This reduces any axial shifting ofthe wheel 100 in respect to the spindle 20 upon the pressurization ofthe brake assembly 50. This lengthens the service life of the package.

This dynamic seal 46 is also the only high pressure seal in the entiredevice which will routinely be subject to rotary movement betweenadjoining parts (all of the other parts of the brake assembly 10 areeither located between two relatively immovable parts—the unitaryhousing 60 for example—or are located between a part which will besubject to rotative forces only during engagement and disengagement—thepiston 57 for example. This design minimizes the necessity of complexmanufacturing processes on adjoining parts (for example grinding) whilealso lowering the cost of parts (larger diameters of seals are ofsignificant cost).

The brake mechanism 50 sits surrounding the spindle so as tomechanically rotatively interconnect the tire 100 to the spindle 20 aswell as providing for a compact engagement mechanism.

The particular braking mechanism 50 includes a reaction support member51, a housing 60, and a spinner nut locking member 80.

The reaction support member 51 serves to interconnect the housing 60with the outer needle bearing 41 thus to pass any radial forcestherebetween. In addition the reaction support member 51 has an oilpassage 52 which extends from the reduced oil passage extension 45 tothe main activation cavity 54 adjacent piston 57. As the activationcavity 54 is located between first and second piston seals 55, 56 thepressurization of the passage 26 in the spindle will cause movement ofthe piston 57 against the force of the disk spring 59 so as todeactivate the braking engagement mechanism. Upon the cessation ofpressurization of the passage in the spindle, the piston 57 will movethe other way due to the force of the disk spring 59, this in turn willengage the braking plates 58 which are connected to the housing 60 withreaction plates 33 which are interconnected to the spindle 20, thus toapply a braking action for the device.

Note that the areas of piston seals 55, 56 are the only location wheresignificant axial movement of two adjoining parts is maintained. As theswept area in the preferred device has both locations on the outercircumferential of a single part, manufacturing can occur at a singlegrinding location. This reduces the cost of the device. (Since thepiston seals 55, 56 are reset into grooves in the piston 57, the pistoncan be turned.) Note also that it is possible to assemble the piston 57and reaction support member 51 together for later incorporation as anintegral unit into the remainder of the device 10. This allows thepremanufacture of this unit in one location (preferably along with seal46) with integration to the remainder of the device occurring in anotherless precise location; all important seals 65, 66 (and 46) arephysically protected. The locations can be very remote or even acrossthe country from each other. This is aided by the fact that except forthese parts the other dimension that should be held is the outer surfaceof the reduced oil passage section 45 of the spindle 20.

The spinner nut locking member 80 serves a dual purpose of assisting inthe weight loading from the wheel 100 and the housing 60 to the exteriorsurface of the reaction support member 51 (which then passes along tothe spindle 20 through bearing 41). The spinner member 80 thus functionsas an integral weight transfer process. The spinner member 80 inaddition also axially pressure preloads the inner edge of the diskspring 59. This provides the engagement forces for the braking mechanism50. Note that it is preferred that the spinner nut 80 in contact withthe adjacent shoulder 53 of the reaction member 51 to provide for areliable braking force across individual units within any series ofdevices 10. Note that it is preferred to assemble the entire devicebefore adding the spinner nut. Assembly can thus occur with hand toolswithout regard for the loading of the spring 59. The spinner nut canthen be included with a spanner wrench. (The screw threads outside thenut would provide the leverage to compress the spring 59.)

The housing 60 serves to contain the spindle 20 and braking mechanism 50in addition to providing an integral weight transferring hub for thetire 100.

In respect to containing the braking mechanism 50, the wheel 100 issubstantially the same inner and outer diameter and width as it would bewithout such mechanism. This allows a given manufacturer to produce bothbraked and unbraked designs with a single frame. This would includeother parts associated with the frame as the main addition to unbrakedunits is the addition of pressure line 205.

In respect to the transfer of weight, the housing 60 shown is primarilymade of two cylindrical plates 62, 63 and a surrounding hub 64. In theembodiment shown, all of these pieces are integrally interconnectedtogether via a series of hex screw bolts 70 that extendcircumferentially about the device from both ends.

The inner cylindrical plate 63 of the housing is interconnected to thespindle 20 directly through the main bearing 31. The fact that allpieces are radially aligned facilitates the weight transfer between theparts, enabling them to function as a single unitary piece. Due to thisbearing and the existence of snap rings 35 (one internal, one external),this cylindrical plate 63 of the housing is not able to shift axially ofthe device. As the other housing parts 62, 64 are integrally connectedto this plate 63, the plate 63 thus serves as the primary retentionmechanism between the spindle and the remainder of the brake assembly50.

The outer cylindrical piece 63 passes its forces through the spinner nutlocking member 80 which is itself securely interconnected through thereaction support member 51 to the inner bearing 41. This allows forceson the outer end of the assembly to pass through the needle bearing 41into the secondary bearing area 40 of the fixed spindle 20.

The tire 100 completes the assembly 10. This tire 100 is directlyinterconnected to the housing 60 so that this housing serves as a hubfor the tire. This allows the assembly 10 to have a smaller diameter andless complicated construction than with the alternative of a separatewheel hub.

Note that the load of the tire 100 surrounds the two bearings 31, 41.The radial transfer of forces between the two is thus readilyaccomplished. Further, since virtually all of the brake mechanism 50rotates at the same time and at the same speed of the tire 100 there isno need for complicated fluid passages or seals: the dynamic seal 46provides for substantially all of the rotational movement betweenadjoining parts in the device. The remaining seals are static seals(mostly relative to the housing 60, reaction support member 51), orsubject to small movements under limited condition (the piston seals 55,56 during a transition between the two operating states of the brake—onor off).

The particular preferred embodiment has a tire 100 substantially 12″ indiameter and 4.3″ in width. The total unit is 5″ wide including spindleplate 21. The tire has a depth of 1+¾″ to the outer diameter of thehousing 60. The support piston 57 has a hydraulic cavity 54 with anouter diameter of 5+⅜″ and an inner diameter of 3+⅛″. The reduced oilpassage extension 45 of the piston has a diameter of 0.5″. The diskspring 59 is 6″ in diameter with an initial depth of 0.38″. It developssubstantially 500000 pounds of force at 0.09″ deflection.

The preferred embodiment of the invention discloses a method ofmanufacture including preassembly of the reaction member and piston, theloading of the spring by the spindle nut, the multi-piece housing, andthe modifications of the spindle mounting plate to accomplish differingframes. The use of a novel seals (only three seals between moveableparts) and the reduced sized oil passage extension simplify and lengthenthe service life of the assembly. The availability of room about theouter end of the spindle for the brake and the use of the intermediatereaction support member shorten the unit to substantially the width ofthe surrounding tire. The oil passage is simple through the spindle,with a double back path to the brake piston cavity. The total unit canbe used without the brake package without structural modification. Asingle ball bearing serves as a main bearing as well as the thrustbearings. It is further possible to remanufacture the device from oneend.

Note that due to the simplicity of the structure of the brake assembly,alternate applications can be readily handled by a single design. Forexample, the spindle mounting plate 20 serves to integrate the brakeassembly 10 with its associated device. It is a fairly easy matter todesign and make differing spindle mounting plate 21 to provide for awide number of differing applications with a basic single device.Further, maintenance of the device is facilitated: by removing thespinner nut locking member 80 and the outer hex screw bolts 70 it ispossible to entirely disassemble the braking mechanism to replace anypressure components or disk components therein without significantcompromise to the overall structural strength of the device oncereassembled. Additional example, the moving parts of the brake (disks33, 58; piston 57; disk spring 59; and, seal 46) can be entirely omittedwithout structural compromise to the tire/spindle weight supportiverotary interconnection. Therefore, although the invention has beendescribed in its preferred form with a certain degree of particularity,it is to be understood that modifications can also be made withoutdeviating from the invention as hereinafter claimed.

1. A brake assembly for a wheel used with a device having a frame, saidassembly comprising a spindle, said spindle having a flange, said flangeof said spindle being connected to the frame, a housing, said housingsurrounding said spindle, a bearing, said bearing being locatedsurrounding said spindle neighboring said flange extending between saidspindle and said housing, means to connect said bearing to said spindlepreventing axial movement therebetween, means to connect said bearing tosaid housing preventing axial movement therebetween, brake disks, saidbrake disks extending between said spindle and said housing on theopposite side of said bearing from said flange, a brake operatingsystem, said brake operating system being located in said housing on theopposite side of said brake disks from said bearing, and means toselectively operate said brake operating system.
 2. The brake assemblyof claim 1 characterized by the addition of a second bearing, and saidsecond bearing extending between said spindle and said housing radiallywithin the confines of said brake operating system.
 3. The brakeassembly of claim 1 characterized in that said brake operating systemincludes a pressure line in said spindle, said spindle having an outerend, and said pressure line extending in said spindle to said outer endthereof.
 4. The brake assembly of claim 3 characterized in that saidouter end of said spindle has a reduced diameter in respect to theremainder of said spindle, a dynamic seal, and said dynamic sealextending between said reduced diameter and said housing allowing for ahigh pressure dynamic seal upon the rotation of said housing in respectto said spindle.
 5. The brake assembly of claim 4 characterized in thatsaid dynamic seal is radially outwards of said reduced diameter of saidspindle.
 6. The brake assembly of claim 4 characterized by the additionof a second bearing and said second bearing extending between saidspindle and said housing between said dynamic seal and said brake disks.7. The brake assembly of claim 6 characterized in that said brakeoperating system is radially outwards of said second bearing.
 8. Thebrake system of claim 1 characterized in that said housing is amulti-part construction with at least one part being removable withoutcompromising the connection of said bearing to said spindle or saidhousing.
 9. The brake system of claim 8 characterized by said brakeoperating system including a biasing spring, and the connection of saidone part to said housing engaging said biasing spring in respect to saidhousing.
 10. The brake system of claim 1 characterized in that saidflange of said spindle extends in a hole in the frame, and said hole inthe frame partially surrounding said flange.
 11. The brake system ofclaim 3 characterized in that said brake operating system includes apiston, said piston being in said housing radially outwards of saidspindle between said outer end and said brake disks.
 12. The brakeassembly of claim 4 characterized in that said dynamic seal is the onlysuch seal in said brake operating system.
 13. The brake assembly ofclaim 1 characterized in that substantially all of said brake operatingsystem can be removed without compromising the connection between saidhousing and said spindle through said bearing.
 14. A brake assembly fora wheel used with a device having a frame, said assembly comprising aspindle, said spindle having a flange, said flange of said spindle beingconnected to the frame, a housing, said housing being a multi-partconstruction with at least one part being removable without compromisingthe connection of said bearing to said spindle or said housing, saidhousing surrounding said spindle, a bearing, said bearing being locatedsurrounding said spindle neighboring said flange extending between saidspindle and said housing, means to connect said bearing to said spindlepreventing axial movement therebetween, means to connect said bearing tosaid housing preventing axial movement therebetween, a second bearing,said second bearing extending between said spindle and said housingradially within the confines of said brake operating system, brakedisks, said brake disks extending between said spindle and said housingon the opposite side of said bearing from said flange, a brake operatingsystem, said brake operating system being located in said housing on theopposite side of said brake disks from said bearing, said brakeoperating system including a pressure line in said spindle, said spindlehaving an outer end, said pressure line extending in said spindle tosaid outer end thereof, said outer end of said spindle having a reduceddiameter in respect to the remainder of said spindle, a dynamic seal,said dynamic seal extending between said reduced diameter and saidhousing allowing for a high pressure dynamic seal upon the rotation ofsaid housing in respect to said spindle, and means to selectivelyoperate said brake operating system.
 15. The brake assembly of claim 14characterized in that said dynamic seal is radially outwards of saidreduced diameter of said spindle.
 16. The brake assembly of claim 14characterized by said second bearing extending between said spindle andsaid housing between said dynamic seal and said brake disks.
 17. Thebrake assembly of claim 14 characterized in that said brake operatingsystem is radially outwards of said second bearing.
 18. The brake systemof claim 14 characterized by said brake operating system includes abiasing spring, and the connection of said one part to said housingengaging said biasing spring in respect to said housing.
 19. The brakesystem of claim 14 characterized in that said flange of said spindleextends in a hole in the frame, and said hole in the frame partiallysurrounding said flange.
 20. The brake system of claim 14 characterizedin that said brake operating system includes a piston, said piston beingin said housing radially outwards of said spindle between said outer endand said brake disks.
 21. The brake assembly of claim 14 characterizedin that substantially all of said brake operating system can be removedwithout compromising the connection between said housing and saidspindle through said bearing.
 22. A method for assembling a brakeutilizing a spindle, the method comprising assembling most of thehousing of the brake including a surrounding wheel, said assemblyincluding a single bearing axially locating the housing in respect tothe spindle and most of a brake operating system, and then finishingassembling the housing including at least one part of which completesthe brake.
 23. A brake assembly for a wheel mounted via a spindle to aframe of a device, the brake assembly wherein the brake is internal ofthe wheel.